1. Field of the Invention
The present invention relates to a porous plate-shaped filler aggregate used while contained in a heat-insulation film for improving heat insulation effect, a producing method therefor and the heat-insulation film containing the porous plate-shaped filler aggregate.
2. Description of Related Art
A heat-insulation film such that porous fillers with low thermal conductivity are dispersed and disposed in a matrix made of resin is known as a heat-insulation film for improving heat insulation effect and flame retardance of an object by forming on the surface of the object. In Patent Document 1, porous plate-shaped fillers with an aspect ratio of 3 or more, a minimum length of 0.1 to 50 μm and a porosity of 20 to 99% are disclosed as the fillers contained in a heat-insulation film. The heat-insulation film performs high heat insulation effect when such porous plate-shaped fillers are disposed in a layered state (laminated) in the heat-insulation film.
Also, in Patent Document 1, a method for firing a green sheet formed out of a material containing ceramic powder to grind after firing is disclosed as a producing method for such porous plate-shaped fillers. In addition, a method for producing porous thin plate-shaped fillers without grinding after firing by firing after performing processing such as cutting and punching into a predetermined planar shape in a state of a green sheet before firing is disclosed as another producing method.